The last federal gun control measure was enacted in 2007 following the Virginia Tech massacre that spring.

CQ Roll Call combed its archives and chronicled Congress’ response to high-profile mass shootings in the nine years since. We also looked at the number of gun control or gun-focused bills and amendments considered — but rarely passed — by Washington lawmakers in response.

A D.C. requirement to show "good reason" for a concealed carry permit has been blocked by a federal judge. (CQ Roll Call file photo)

A federal judge has stopped Washington, D.C., from enforcing a requirement that concealed carry applicants show "good reason" to obtain a license.

U.S. District Judge Richard Leon's preliminary injunction on Tuesday is the latest development in a court fight that began several years ago. The case, Palmer v. District of Columbia, was filed in 2014, challenging the District's law which required gun owners to demonstrate a "good" or "proper" reason to obtain a concealed carry permit.